1. Field of the Invention
This invention relates to synthetic fibers useful for coverstock of disposable diaper, sanitary napkin, etc.
2. Description of the Related Art
Disposable diaper, etc. are composed of three layers of a coverstock layer, an absorbent layer and a backing layer in the order from the side where they contact with skins at the time of wearing. For the coverstock are required not only water-permeability due to which a liquid to be absorbed is rapidly transferred to the absorbent layer, but also dry touch property affording a dry feeling to skins by preventing the backflow of the absorbed liquid. Hydrophilic properties are required for improving the water-permeability, while hydrophobic properties are required for obtaining the dry touch property In order to achieve such contrary objects, these has been proposed a non-woven fabric obtained by adhering a small quantity of a mixture of surfactants onto hydrophobic fibers of polyolefin or polyester, thereby imparting the desired hydrophilic properties (Japanese patent application laid-open Nos. Sho 63-6166/1988 and Sho 63-49158/1988).
In the case of the diaper using the coverstock made of the hydrophobic fibers having surfactants adhered thereonto as described above, when a liquid is once or twice absorbed therein, the surfactants flow out from the coverstock rapidly and water-permeability is reduced; hence when it is used for a long time, over night for example, a disagreeable sticky feeling occurs.